In recent years, the number of atopic dermatitis patients has been increasing drastically. With the ratio of atopic dermatitis patients exceeding 30% of dermatological patients, atopic dermatitis is a predominant skin disease. Atopic dermatitis is an atopic disease that is caused by genetic factors more likely to produce IgE antibodies against usual antigens, plus various environmental factors. This disease develops in infancy, takes a chronic course with aging, and mostly remits before adolescence. However, some cases persist even after adolescence or develop after adolescence. Most cases in adults are particularly intractable, and remission is hardly expected as they are more aged. The established lesions are lichenified with serious and often spasmodic itching, resulting in frequent exacerbations and remissions with certain association with other atopic diseases.
Much remains to be revealed about a mechanism underlying the development of such atopic dermatitis. There is also a problem with discrimination from other skin diseases. Thus, a treatment method thereof has not been established yet. Attempts have previously been made, such as the external use of adrenal corticosteroids, the medication of an antihistaminic agent or chemical transmitter release inhibitor, or diet therapy in which egg, milk, soybeans, and so on are removed from food materials, the removal of antigenic substances such as mites and fungi (molds) from living environments, etc. However, the medication still faces a problem in adverse reaction, because the drug is used in children in their growing years, furthermore over a long period. Moreover, the diet therapy or the measure to remove environmental antigens has the difficulty in completely removing antigens and has the problem that mental burden is also great.
In light of such circumstances, studies have been conducted recently to elucidate a mechanism underlying the development of atopic dermatitis by making full use of molecular biological findings, while enhancing therapeutic effect by inhibiting a portion of the development mechanism. For example, a method focusing on the fact that the production of IgE antibodies against antigens is partially responsible for the mechanism to cause symptoms, as described above, has been proposed, and this method involves alleviating symptoms by the external use of a substance inhibiting the production of IgE antibodies against antigens (Japanese Patent Laid-Open Publication Nos. 109290/1995, 109292/1995, and 100236/1997).
Meanwhile, it has previously been reported an antigenic substance that is contained in sweat and induces atopic dermatitis (WO 03/084991 A1; Japanese Patent No. 3983260; and the year 2002 Health Labour Sciences Research Grant, Research Report of Research on Allergic disease and immunology (First Part, p. 101-103, issued on March 2003 by the Japanese Ministry of Health, Labour and Welfare)). However, neither has this antigenic substance been identified, nor an antibody that inhibits the histamine releasing activity of the antigenic substance has been reported.